Life in the Middle Ages was dangerous. Whether living in a communal setting, fighting abroad, or simply tending a field, there were numerous challenges that could bring it all to an end. Life inside a castle or a monastery may have offered some protection, but you were just as exposed to horrible, contagious diseases as everyone else.
As they developed, medieval cities were particularly susceptible to afflictions resulting from a lack of hygiene, poor sanitation, and overcrowding. Such poor hygiene practices certainly contributed to the spread of the Black Plague. Many diseases that affected people during the medieval period were similar to those of the ancient world or continued on through the early modern period. Others have mysteriously reappeared today, hundreds of years later. Luckily, better understanding and medical technology have brought on cures, treatments, and preventatives that make them far less devastating.
With all of the potential risks to a person's health that existed in a medieval city, the Middle Ages may have been one of the most dangerous eras in history.
Caused by the Mycobacterium leprae bacteria, leprosy is, arguably, as misunderstood today as it was during the Middle Ages. Now called Hansen's Disease, leprosy results in skin lesions and nerve damage that can impair a person's eyes and limbs. Leprosy develops slowly, and visible symptoms can take decades to manifest.
In medieval society, lepers were shunned and cast out of cities, towns, villages, and even the smallest of communities. Leper hospitals were established outside of town centers during the 12th century in France and the Low Countries. Facilities tasked to solely care for lepers were known as leprosaria (or leprosariums) and fell under the charitable auspices of the Church.
Leprosy was common in both the Byzantine Empire and Western Europe from the 12th century forward, often transferred by pilgrims and Crusaders. Lepers were refused burial alongside non-lepers thanks to the Old Testament passage Leviticus 13:44-46:
He is leprous, he is unclean. The priest shall pronounce him unclean; the disease is on his head. The person who has the leprous disease shall wear torn clothes and let the hair of his head be disheveled; and he shall cover his upper lip and cry out, “Unclean, unclean.” He shall remain unclean as long as he has the disease; he is unclean. He shall live alone; his dwelling shall be outside the camp.
The social class of the leper dictated their overall reception, however. Alice the Leper, a lay sister from the Cistercian monastic order, remains the patron saint of the blind and the paralyzed after becoming both due to her leprosy.
The Black Plague spread from Asia into Europe during the mid-14th century, resulting in millions of casualties in the process. No one was immune from the Black Plague, a general term for the three different types of plague caused by the Yersinia pestis bacteria. Most commonly spread by infected fleas carried on cargo ships, the plague could manifest in bubonic, pneumonic, and septicemic forms.
The bubonic plague affected one's lymphatic system, causing swelling and discoloration of the areas around the lymph nodes - known as buboes. The pneumonic plague infiltrated the lungs, while the septicemic plague resulted when the bacteria entered an individual's bloodstream. The pneumonic was the most dangerous and infectious because it could be transmitted through airborne blood droplets.
According to 14th-century Italian poet Giovanni Boccaccio, the plague affected "men and women alike... at the beginning of the malady, certain swellings, either on the groin or under the armpits… waxed to the bigness of a common apple, others to the size of an egg, some more and some less, and these the vulgar named plague-boils.”
Other symptoms included fever, vomiting, body aches, and, more than 50% of the time, loss of life. The Black Plague terrified everyone:
One citizen avoided another, hardly any neighbour troubled about others, relatives never or hardly ever visited each other. Moreover, such terror was struck into the hearts of men and women by this calamity, that brother abandoned brother, and the uncle his nephew, and the sister her brother, and very often the wife her husband. What is even worse and nearly incredible is that fathers and mothers refused to see and tend their children, as if they had not been theirs.
There were so many cadavers in many medieval towns and cities that they reportedly "[f]illed every corner... Although the cemeteries were full they were forced to dig huge trenches, where they buried the bodies by hundreds."
St. Anthony's Fire, caused by eating grains contaminated with the Claviceps purpurea fungus, is also known as ergotism. The ergot fungus grows on moldy grains and, once ingested, can cause redness, swelling, and gangrene. Rye was produced and consumed in large quantities by the poor and was especially susceptible to the ergot fungus, so the disease affected the lower classes in the greatest numbers.
When one is first struck with St. Anthony's Fire, red spots appeared on the flesh. The initial burning soon becomes excruciating as limbs swell; people often hallucinate, with some in the past believing they were in a fight with the devil. Sometimes, people have convulsions, but as their extremities begin to rot, toes, fingers, ears, and even arms or legs can fall off. Based on an account of the St. Antony's Fire outbreak that struck southern France during the 10th century:
The afflicted thronged to the churches and invoked the saints. The cries of those in pain and the shedding of burned-up limbs alike excited pity; the stench of rotten flesh was unbearable.
In 944 CE, 40,000 people in France perished from St. Anthony's Fire, and monastic hospitals were built throughout Europe to treat victims.
Largely associated with England, "sweating sickness" appeared several times from 1485 to the late 16th century. In 1485 alone, sweating sickness took the lives of 15,000 people in London. After the initial onslaught of the disease, it faded until 1508 and reappeared again in 1517. The sweating sickness jumped to Continental Europe and struck Flanders, Germany, Sweden, and several other locations during the 1520s before it reemerged in England for the last time in 1551.
The initial symptoms of the sweating sickness were "a sense of apprehension" followed by headaches, pain in one's back and shoulders, and nausea. This was followed by excessive sweating, delirium, and abdominal pain. The more severe symptoms lasted anywhere from 15 to 21 hours and accompanied extreme fatigue which could result in a coma or loss of life.
The sweating sickness mostly affected the upper class and could end the life of an adult in a matter of hours. During the outbreak of 1529, King Henry VIII so feared getting the disease that he "left in great haste, and went a dozen miles off" to hide from the affliction.
Researchers have theorized that the sweating sickness was caused by typhus, influenza, botulism, or the hantavirus, but no definitive source of the disease has been found.